We develop a campaign model for counterinsurgency that is derived from the Lanchester-inspired Vidale-Wolfe marketing model utilized in the analysis of a consumer population's dynamics. We adapt this approach for a situation in which the output of our differential equation model is not attrition but the percentage of a given population that supports a particular side in the insurgency. The model is descriptive, providing a structured framework to analyze complex inputs in a simple,...

Topics: Counterinsurgency, Differential equations

40
40

May 8, 2012
05/12

by
Brita Immergut

texts

######
eye 40

######
favorite 0

######
comment 0

Topics: Mathematics, Equations

This final report presents the results of the research performed under ONR grant number N00014-07-1-0043 over the period of February 1st, 2007 to January 1st, 2010. The research team working on this project consists of Prof. Moeness Amin (PI), Prof. Fauzia Ahmad (Research Professor), Dr. Yeo-Sun Yoon (Postdoctoral Fellow), and Mr. Pawan Setlur (Graduate Student). The research efforts over the life of this grant have evolved around (1) Maximum Likelihood and Suboptimal Schemes for Micro-Doppler...

Topics: DTIC Archive, VILLANOVA UNIV PA, *RADAR IMAGES, *TARGET DETECTION, *URBAN AREAS, WAVEFORMS, DOPPLER...

The bottom line of this work is to develop affordable numerical methods in the context of stochastic homogenization. Many partial differential equations of materials science indeed involve highly oscillatory coefficients and small length-scales. Homogenization theory is concerned with the derivation of averaged equations from the original oscillatory equations, and their treatment by adequate numerical approaches. Stationary ergodic random problems (and the associated stochastic homogenization...

Topics: DTIC Archive, ECOLE NATIONALE DES PONTS ET CHAUSSEES (FRANCE), *PROBLEM SOLVING, *UNCERTAINTY,...

The discrete resonance frequency spectrum is derived for an m-layered Goupillaud-type elastic medium subjected to a discrete, time-harmonic forcing function at one end, with the other end fixed. Analytical stress solutions are derived from a global system of recursion relationships using z-transform methods, where the determinant of the resulting global system matrix Am in the z-space is a palindromic polynomial with real coefficients. The zeros of the palindromic polynomial are distinct and...

Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *HARMONIC ANALYSIS, *RESONANCE,...

There are several studies in the literature regarding the equation of state of alumina-epoxy composites. Although these single component systems interact in a complex manner with shock waves, the addition of a second metal or ceramic particulate can result in even more complex interactions. This paper presents the shock equation of state results on a multi-phase composite Al-MnO2-epoxy. Equation of state experiments were conducted using three different loading techniques - single state light...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE, *EPOXY COMPOSITES, *SHOCK,...

The configuration design space and flight regime of new air vehicles is vast. Determination of nonlinear aeroelastic responses, vehicle trim states and vehicle stability is a challenge that must be addressed in an efficient, methodical manner. To accomplish this, we are developing a method for determining and analyzing nonlinear aeroelastic responses using a combination of a continuation method with a variable-fidelity reduced-order model of the flowfield, a nonlinear description of structural...

Topics: DTIC Archive, TEXAS ENGINEERING EXPERIMENT STATION COLLEGE STATION, *AEROELASTICITY, *MATHEMATICAL...

This report presents a theoretical framework for minimising a quadratic objective function subject to a quadratic equality constraint. The first part of the report gives a detailed algorithm which computes the global minimiser without calling special nonlinear optimisation solvers. The second part of the report shows how the developed theory can be applied to solve the time of arrival geolocation problem.

Topics: DTIC Archive, DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA) ELECTRONIC WARFARE...

The long-term goals of this research project are to advance data assimilation (DA) methods for coastal ocean circulation models. After several years of research focused on various aspects of advanced, variational DA with nonlinear coastal ocean models, we have come close to development of an optimal, versatile, and relocatable DA system based on a primitive equation model with a turbulence submodel. The system can be used efficiently both for operational needs (forecasting, search and rescue,...

Topics: DTIC Archive, OREGON STATE UNIV CORVALLIS COLL OF OCEANIC AND ATMOSPHERIC SCIENCES, *OCEAN...

The long-term scientific goals of this research project are: 1. To develop an understanding of how some sources of error affect ocean predictability. 2. To gain experience and develop ideas for the limitations to the predictability of oceanic processes. The primary objectives of this project are: (i) to undertand the importance of model uncertainty; (ii) to assess the influence of uncertainty on predictability; and (iii) to collaborate and learn from fellow BRC projects. To improve forecasts of...

Topics: DTIC Archive, HAWAII UNIV HONOLULU, *FORECASTING, *PREDICTIONS, *OCEANS, *OCEAN CURRENTS,...

Object correlation and maneuver detection are persistent problems in space surveillance and space object catalog maintenance. This paper demonstrates the utility of using quadratic trajectory control cost, an analog to the trajectory L2-norm in control, as a distance metric with which to both correlate object tracks and detect maneuvers using Uncorrelated Tracks (UCTs), real-time sensor measurement residuals, and prior state uncertainty. State and measurement uncertainty are incorporated into...

Topics: DTIC Archive, COLORADO UNIV AT BOULDER DEPT OF AEROSPACE ENGINEERING SCIENCES, *CORRELATION, *SPACE...

The small signal modulation of a vertical external cavity surface emitting laser (VECSEL) is examined. The modulation transfer function (MTF) of the cavity is measured for multiple photon lifetimes operating between Class A and Class B regimes, where the photon and carrier lifetimes are of the same order. Three coupled ordinary differential equations with similarities to an electrically-injected quantum-well laser with a separate confinement heterostructure are used to mathematically describe...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE COMPONENTS AND SUBSYSTEMS...

Overall objective of this research effort is to understand and explain ultrafast carrier scattering dynamics in semiconductor heterostructures. Specific research objectives are: To develop a screened semiconductor Bloch formalism to provide the force-balance equation with a friction force that determines electron drift velocity, and to establish screened semiconductor Bloch equations to study the dynamics of electron impurity, roughness, phonon, electron scattering, and dynamics of optical...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE, *SEMICONDUCTORS,...

The mechanisms of ion wind generation in surface dielectric barrier discharges (SDBDs) is identical to the one in corona discharges. The electrohydrodynamic force (EHD) generated in SDBDs for moderate increase rates of the applied voltage is, as in corona discharges, due to the development of a unipolar region above the dielectric surface, where ion space charge is dominant and ions transfer momentum to the neutral gas. For very fast rise (few ns) of the applied voltage, ion wind is no longer...

Topics: DTIC Archive, UNIVERSITE PAUL SABATIER TOULOUSE (FRANCE), *DIELECTRICS, *AERODYNAMIC FORCES,...

The present paper highlights results derived from the application of a high-fidelity simulation technique to the analysis of low-Reynolds-number transitional flows over moving and flexible canonical configurations motivated by small natural and man-made flyers. This effort addresses three separate fluid dynamic phenomena relevant to small fliers, including: laminar separation and transition over a stationary airfoil, transition effects on the dynamic stall vortex generated by a plunging...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIR/ AERONAUTICAL...

The shock properties of Bitossi Corbit 98 have been investigated. The Hugoniot Elastic Limit (HEL) was determined to be 7.96 + or - 1.5 and 8.27 + or - 0.8 GPa in two separate experiments. The strength in tension was found to be 0.271 GPa. The Hugoniot equation of state for elastic compression was calculated to be: Us=0.936*Up+10.53 This ceramic material--98% Al2O3--has been selected as the first component in a new layered armor design, which requires knowledge of the information discussed. The...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *CERAMIC MATERIALS, *ALUMINUM OXIDES,...

A computational approach to homogeneous nucleation is proposed, based on Eulerian description of the gas phase coupled with a Lagrangian approach to the cluster phase. A continuum, Euler / Navier-Stokes solver VAC is used to model the gas transport, and a kinetic particle solver is developed in this work to simulate cluster nucleation and growth. The new model was found to reproduce well the known theoretical dimer formation equilibrium constants for two gases under consideration, argon and...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE, *PLUMES, COMPUTERIZED...

Many combat and agent-based models use time-step as their simulation time advance mechanism. Since time discretization is known to affect the results when numerically solving differential equations, it stands to reason that it might likewise affect the results of such simulations. This paper demonstrates that is indeed the case. Using simple queueing models, we demonstrate that the size of the time step can have a substantial impact on estimated measures of performance. While large time steps...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA MODELING VIRTUAL ENVIRONMENTS AND SIMULATION...

We develop a method for non-paraxial beam propagation that obtains a speed improvement over the Finite-Difference Split-Step method (FDSSNP) recently reported by Sharma et al. The method works in the eigen-basis of the Laplace operator, and in general requires half as many operations to propagate one step forward so that a 2X speedup can be realized. However, the new formulation allows the Fast Fourier Transform (FFT) algorithm to be used, which allows an even greater speedup. The method does...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB BROOKS CITY-BASE TX HUMAN PERFORMANCE WING (711TH), *BEAM...

Pursuit strategies for interacting particles and feedback laws to execute them are formulated in three dimensions focusing on constant bearing (CB) pursuit - a case of interest in biology. In the analysis of such laws for the setting of n particles engaged in cyclic pursuit, we reveal interesting invariant manifold dynamics and associated explicit integrability properties, as well as conditions for special solutions such as relative equilibria.

Topics: DTIC Archive, MARYLAND UNIV COLLEGE PARK DEPT OF ELECTRICAL AND COMPUTER ENGINEERING,...

Iron-gallium alloys Fe(sub 1-x)Ga(sub x) exhibit an exceptional increase in magnetostriction with gallium content. We present small-angle neutron scattering investigations on a Fe(sub 0:81)Ga(sub 0:19) single crystal. We uncover heterogeneities with an average spacing of 15 nm and with magnetizations distinct from the matrix. The moments in and around the heterogeneities are observed to reorient with an applied magnetic field or mechanical strain. We discuss the possible roles played by...

Topics: DTIC Archive, MARYLAND UNIV COLLEGE PARK DEPT OF MATERIALS SCIENCE AND ENGINEERING, *GALLIUM,...

A new shock-fitting algorithm has been introduced for accurate computation of the dynamics ol mulli-dimensional detonations. First detailed verification of detonation stability theory in two dimensions. The algorithm has been extended to: 1) multi-step chemistry, 2) non-ideal equation of state, and 3) radially expanding detonations. The algorithm is proposed as a new tool for direct numerical compulation of detonation instability as an alternative for analytically and numerically tedious...

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH CAMBRIDGE, *DETONATION WAVES, ACCURACY, ALGORITHMS,...

DRDC Atlantic ordered the Maritime Research Institute Netherlands (MARIN) to perform a study on the hydrodynamic efficiency for frigate/destroyer type of vessels in order to improve their requirements for the allowable fuel consumption. MARIN proposed to evaluate the model test results of about 15/20 frigates from NATO related countries and to present this in dimensionless tables and diagram form. The report will contain a section describing how the derived data have been obtained from the...

Topics: DTIC Archive, MARITIME RESEARCH INST NETHERLANDS WAGENINGEN, *DESTROYERS, *FRIGATES, *FUEL...

This report presents numerical procedures for solving the equations of Magneto-Fluid-Dynamics (MFD). These equations consist of the Navier-Stokes equations coupled to the full set of Maxwell's equations. They govern flow within electromagnetic fields. The primary interest to the Air Force of this work is flow control about aerodynamic vehicles and thrust enhancement within scramjet engines via the interaction of external electromagnetic fields, produced on board, with the high speed flow about...

Topics: DTIC Archive, STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS, *ELECTROMAGNETIC FIELDS,...

The Jones-Wilkins-Lee-Baker (JWLB) equation of state was developed to more accurately describe overdriven detonation, while maintaining an accurate description of high explosive products expansion work output. The increased mathematical complexity of the JWLB high explosive equations of state provides increased accuracy for practical problems of interest. Increased numbers of parameters is often justified based on improved physics descriptions, but can also mean increased calibration...

Topics: DTIC Archive, ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ...

One path to scientific discovery is that a theoretical argument leads to a clear question that can be answered only by experiment. An experiment is a question asked of nature. If the question is asked in such a way that nature is able to answer it with a whole page, it is like the answer of a politician from which one is often left wondering what he said. The experiment therefore has to be formulated in such a way that nature is forced to say yes or no . Of course, to be able to formulate the...

Topics: DTIC Archive, CALIFORNIA INST OF TECH PASADENA GRADUATE AEROSPACE LABS, *BOUNDARY LAYER TRANSITION,...

A number of challenges in the development and application of flying qualities criteria for modern aircraft are addressed in this dissertation. The history of flying qualities is traced from its origins to modern day techniques as applied to piloted aircraft. Included in this historical review is the case that was made for the development of flying qualities criteria in the 1940s and 1950s when piloted aircraft became prevalent in the U.S. military. UAVs today are in the same context...

Topics: DTIC Archive, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG, *FLIGHT CONTROL SYSTEMS,...

A number of airfoils intended for VTOL/Rotorcraft applications were tested in the Penn State Low-Speed, Low-Turbulence Wind Tunnel, and the results of these tests compared with those predicted using several well-known theoretical methods. The airfoils considered are the E 387 and the S406, S407, S411, S414, and the S415, and the theoretical methods used are the potential-flow/integral boundary-layer methods, PROFIL07 and XFOIL 6.94, the Euler solver/integral boundary-layer method, MSES 3.05,...

Topics: DTIC Archive, AIRFOILS INC PORT MATILDA PA, *AIRFOILS, *AERODYNAMIC CHARACTERISTICS, BOUNDARY...

The Network Connectivity Analysis Model (NCAM) software predicts the viability of links between moving communications nodes. The deployment model tracks the position of the moving nodes as a function of time by having the user outline the platform paths with waypoints and defines the time the platform leaves and arrives at each waypoint. It then interpolates the position of the waypoint at strategically chosen snapshot times. For verification purposes, the derivations of the equations the...

Topics: DTIC Archive, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY LETHALITY ANALYSIS...

Eigenvalue detonation theory has been shown to explain the observed behavior of new aluminized combined effects explosives. An analytical cylinder test model has long been used the U.S. Army Armaments Research, Development and Engineering Center, Picatinny Arsenal, New Jersey for explosive equation of state calibration and verification. The analytic model was originally based on adiabatic expansion along the principle isentrope from the Chapman-Jouguet state. The analytic cylinder test model...

Topics: DTIC Archive, ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ...

USTRANSCOM is currently responsible for the daily shipment of supplies to forward operating bases throughout Afghanistan. Aerial cargo shipments are an important method used to quickly deliver items that are needed immediately. Currently delivery times vary greatly. This variation causes confidence in on-time deliveries to decrease. As a result shipments are demanded early and often, causing bottlenecks in the transportation system and fewer on-time deliveries. This paper analyzes data gathered...

Topics: DTIC Archive, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT,...

The foundation of the theory of functionally graded plates with simply supported edges, under a Friedlander explosive air-blast are developed within the classical plate theory (CPT). Within the development of the theory, the two constituent phases, ceramic and metal, vary across the wall thickness according to a prescribed power law. The theory includes the geometrical nonlinearities, the dynamic effects, compressive tensile edge loadings, the damping effects, and thermal effects. The static...

Topics: DTIC Archive, ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI, *BLAST...

The effect of diverse sources of uncertainties and the intrinsically multi-scale nature of physical systems poses a considerable challenge in their analysis. Such phenomena are particularly critical in material systems where the microstructural variability and randomness at different scales have a significant impact on the macroscopic behavior of the system. Toward this goal, during the period of this grant, we have developed a sophisticated though efficient and accurate multiscale stochastic...

Topics: DTIC Archive, CORNELL UNIV ITHACA NY MATERIALS PROCESS DESIGN AND CONTROL LABORATORY (MPDC),...

A new method of controlling a flapping-wing micro air vehicle by varying the velocity profiles of the wing strokes is presented in this manuscript. An exhaustive theoretical analysis along with simulation results show that this new method, called split-cycle constantperiod frequency modulation, is capable of providing independent control over vertical and horizontal body forces as well as rolling and yawing moments using only two physical actuators, whose oscillatory motion is defined by four...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIR/CONTROL SCIENCES...

The exact inverses of a class of Laplace transforms involving doubly-nested square roots and two branch points are presented. From these results the exact solution of Stokes' first problem, a well known initial-boundary value problems (IBVP) in fluid mechanics, for a micropolar fluid is determined.

Topics: DTIC Archive, NEW ORLEANS UNIV LA DEPT OF MATHEMATICS, *LAPLACE TRANSFORMATION, *CONTINUUM...

This thesis explores the recent rise of skiing and snowboarding injuries from jumps fabricated with no scientific design process. It summarizes a previous method to develop a first order ordinary differential equation (ODE) for the landing surface shape, based on kinematics and dynamics, which limits the equivalent fall height (EFH) on landing. These are compared with theoretical expressions for EFH in tabletop jumps, which are shown to have linearly increasing and possibly large EFH values...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *WOUNDS AND INJURIES, *SKIING, THEORY, SHAPE,...

For Navy relevant geometries, separation of wall bounded flows is a highly complex phenomenon. The combination of three-dimensionality and unsteadiness results in a highly complex time-dependent topology of the separated region. In a combined numerical/experimental effort we investigated laminar separation bubbles in external flows. We employed highly-resolved direct numerical simulations to obtain a deeper understanding of the various physical mechanism governing separation, transition, and...

Topics: DTIC Archive, ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING, *THREE DIMENSIONAL...

Deterministic Galerkin approximations of a class of second order elliptic PDEs with random coefficients on a bounded domain D is a subset of R(exp d) are introduced and their convergence rates are estimated. The approximations are based on expansions of the random diffusion coefficients in L(exp 2)(D)-orthogonal bases, and on viewing the coefficients of these expansions as random parameters y = y(omega) = (y(sub )i(omega)). This yields an equivalent parametric deterministic PDE whose solution...

Topics: DTIC Archive, TEXAS A AND M UNIV COLLEGE STATION DEPT OF MATHEMATICS, *CHAOS, MATHEMATICAL...

Airspace capacity estimates are important for managing air traffic and predicting the effectiveness of new airspace designs and proposed decision support tools. Because air traffic management relies on manual procedures, controller workload determines the traffic limit of most sectors. Current operational procedures for estimating capacity in United States airspace do not account for conflict avoidance and recurring workload. This paper examines a more complete analytical model. Each sector has...

Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *AIRCRAFT, *REGRESSION ANALYSIS,...

We study the few-electron eigenspectrum of a carbon-nanotube double quantum dot with spin-orbit coupling. Exact calculation are combined with a simple model to provide an intuitive and accurate description of single-particle and interaction effects. For symmetric dots and weak magnetic fields, the two-electron ground state is antisymmetric in the spin-valley degree of freedom and is not a pure spin-singlet state. When double occupation of one dot is favored by increasing the detuning between...

Topics: DTIC Archive, COLORADO UNIV AT BOULDER, *CARBON NANOTUBES, *QUANTUM DOTS, EIGENVALUES, ENERGY GAPS,...

In this research, the rate constitutive theories for ordered thermoviscous fluids, ordered thermoelastic solids and ordered thermoviscoelastic polymeric fluids in contra- and co-variant bases are developed. Such theories are necessitated when the mathematical models of the deforming matter are derived using the Eulerian description. In each case, the dependent variables in the rate constitutive theory and their argument tensors describing the physics of the deforming matter are identified. The...

Topics: DTIC Archive, KANSAS UNIV LAWRENCE, *MATHEMATICAL MODELS, *THERMOELASTICITY, VISCOELASTICITY,...

A delay differential equation model of a passively mode-locked two-section quantum-dot laser reveals pulse asymmetry that is experimentally confirmed through direct electric-field measurements using frequency-resolved optical gating. This finding indicates that conventional autocorrelators, which obscure the underlying pulse structure due to the symmetry inherent in autocorrelation, are of limited utility in the characterization of these lasers.

Topics: DTIC Archive, NEW MEXICO UNIV ALBUQUERQUE CENTER FOR HIGH TECHNOLOGY MATERIALS, *QUANTUM DOTS,...

This report assesses potential environmental impacts of laser systems on organisms found living in the marine environment. To accomplish this objective, the major laser systems used by the Navy in a marine setting were defined, Environmental Impact Statements (EISs) for various ranges were reviewed, and naval researchers were queried to determine the most prominent laser system usage. Once the predominant laser systems were identified, a list of biological groups that may be affected was...

Topics: DTIC Archive, SPACE AND NAVAL WARFARE SYSTEMS CENTER PACIFIC SAN DIEGO CA, *LASERS, *ENVIRONMENTAL...

The long-term goal is to develop a robust coastal/nearshore modeling system for river plume dynamics, sediment deposition/resuspension and inlet morphodynamics in a wave-dominated, high sediment yield and highly stratified environment. Objectives are: 1) To develop a detailed wave-resolving Reynolds-Averaged Navier-Stokes model for wave-current-sediment interactions in well-mixed and salt-stratified conditions. 2) To study the interactions between tidal flow, waves and riverine outflow and...

Topics: DTIC Archive, DELAWARE UNIV NEWARK CENTER FOR APPLIED COASTAL RESEARCH, *WAVES, *SEDIMENT...

In this investigation, a two-dimensional time-domain closed-form mathematical model for the hydrodynamic forces on the upstream vertical face of a given rigid dam subjected to a specified horizontal ground motion accelerogram was developed. The model includes the absorption of energy at the elastic reservoir bottom, characterized by the impedance ratio of the sub-bottom materials with respect to water . The formulated boundary-value problem is solved in Laplace's domain and subsequently...

Topics: DTIC Archive, ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES...

A series of mine-blast loading experiments were conducted where the soil moisture content, plate standoff distance, and plate shape (flat and V-shaped) were varied. Three experiments were conducted for each test configuration to quantify repeatability of the experiments. The primary experimental diagnostic was the initial velocity imparted to the plate, as inferred from the maximum height that the plate displaced. Numerical simulations were conducted to examine the ability to reproduce the...

Topics: DTIC Archive, SOUTHWEST RESEARCH INST SAN ANTONIO TX, *BLAST LOADS, *COMPUTERIZED SIMULATION, *LAND...

Parametric partial differential equations are commonly used to model physical systems. They also arise when Wiener chaos expansions are used as an alternative to Monte Carlo when solving stochastic elliptic problems. This paper considers a model class of second order, linear, parametric, elliptic PDEs in a bounded domain D with coefficients depending on possibly countably many parameters. It shows that the dependence of the solution on the parameters in the diffusion coefficient is analytically...

Topics: DTIC Archive, PARIS UNIV (FRANCE), *COEFFICIENTS, *STOCHASTIC PROCESSES, *PARTIAL DIFFERENTIAL...

The time-dependent, chemically reacting, viscous fluid dynamics within gas laser mixing systems and pressure recovery systems are simulated using the unsteady, laminar and turbulent multi-component Navier-Stokes equations. The solutions of these equations are generated within simulations of the relevant laser sub-systems at standard operating conditions. The simulations are performed to provide greater insight regarding the physical processes underlying these sub-systems so that these physics...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE, *OXYGEN IODINE...

We extend the computations of ionizing shocks in argon to unsteady and multi-dimensional, using a collisional-radiative model and a single-fluid, two-temperature formulation of the conservation equations, described in part 1 of this article. We show that the fluctuations of the shock structure observed in shock-tube experiments can be reproduced by the numerical simulations, and explained on the basis of the coupling of the non-linear kinetics of the collisional-radiative model with wave...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE, *SHOCK TUBES, *ARGON,...

The need for reform in the Department of Defenses (DoD) acquisition and management of services acquisitions has been recently highlighted by the Government Accountability Office and by top leadership within the DoD acquisition community. However, problems with the acquisition of business-to-business services have not been limited to purchasing in the public sector; industry has also struggled with the effective acquisition of business-to-business services because the complexities and unique...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA GRADUATE SCHOOL OF BUSINESS AND PUBLIC POLICY,...